d-Allulose, a C-3 epimer of d-fructose, has great market potential in food, healthcare, and medicine due to its excellent biochemical and physiological properties. Microbial fermentation for d-allulose production is being developed, which contributes to cost savings and environmental protection. A novel metabolic pathway for the biosynthesis of d-allulose from a d-xylose–methanol mixture has shown potential for industrial application. In this study, an artificial antisense RNA (asRNA) was introduced into engineered Escherichia coli to diminish the flow of pentose phosphate (PP) pathway, while the UDP-glucose-4-epimerase (GalE) was knocked out to prevent the synthesis of byproducts. As a result, the d-allulose yield on d-xylose was increased by 35.1%. Then, we designed a d-xylose-sensitive translation control system to regulate the expression of the formaldehyde detoxification operon (FrmRAB), achieving self-inductive detoxification by cells. Finally, fed-batch fermentation was carried out to improve the productivity of the cell factory. The d-allulose titer reached 98.6 mM, with a yield of 0.615 mM/mM on d-xylose and a productivity of 0.969 mM/h.

中文翻译：

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利用 d-木糖-甲醇混合物增强 d-阿洛酮糖的生物合成及其在大肠杆菌中使用反义 RNA 的自诱导解毒作用


d-阿洛酮糖是d-果糖的C-3差向异构体，由于其优异的生化和生理特性，在食品、保健和医药领域具有巨大的市场潜力。用于生产 d-阿洛酮糖的微生物发酵技术正在开发中，这有助于节省成本和保护环境。从 d-木糖-甲醇混合物生物合成 d-阿洛酮糖的新代谢途径已显示出工业应用的潜力。在这项研究中，将人工反义RNA（asRNA）引入工程大肠杆菌中以减少戊糖磷酸（PP）途径的流动，同时敲除UDP-葡萄糖-4-差向异构酶（GalE）以防止副产物的合成。结果，d-木糖的d-阿洛酮糖产量增加了35.1%。然后，我们设计了d-木糖敏感的翻译控制系统来调节甲醛解毒操纵子（FrmRAB）的表达，实现细胞的自诱导解毒。最后进行补料分批发酵，以提高细胞工厂的生产率。 d-阿洛酮糖滴度达到 98.6 mM，d-木糖产量为 0.615 mM/mM，生产率为 0.969 mM/h。